<!DOCTYPE html>
<style>
    .box { width:66px; height:66px; margin:auto; background:blue; }
</style>
<p>Change an ancestor of a descendant spanner to becoming a spanner, so that the descendant will cease to be a spanner.</p>
<p>There should be three identical blue <em>squares</em> below. The space between them should be equal to the size of the squares.</p>
<div style="width:132px;">
    <div class="box" style="margin-bottom:66px;"></div>
    <div class="box"></div>
    <div class="box" style="margin-top:66px;"></div>
</div>